According to prior art when laying a cable or pipeline offshore the cable or pipeline may be spooled off a reel or drum and lowered into the water through a vertical passage in the vessel. A frame structure may be supported above a such vertical passage, said frame structure including guide means for guiding the cable or pipeline from above and down through the frame structure and the vertical passage. Tensioner means supported in the tower-like frame structure are used for applying tension in the cable or pipeline.
It is also known to handle modules and tools through a vertical passage or moonpool on board a vessel.
Deck space is restricted on board a vessel and valuable deck space will be saved if one could combine the facilities for laying of cables/pipelines with those of handling modules and tools through a moonpool.